Process of treating fibrous material.



UNITED STATES PATENT OFFICE.

I ROBERT R. ROBERTS, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WILLIAM J. ROBINSON, OF NEW YORK, N. Y.

PROCESS OF TREATING FIBROUS MATERIAL.

No Drawing.

Specification of Letters Patent. P t nt d. Mar. 22, 1910.

Application filed May 26, 1909.

Serial No. 498,576.

To all whom it may concern:

Be -1t known that I, ROBERT R. ROBERTS, a

citizen of the United States, residing at closely associated with the fiber.

' by which lVashington, in the District of- Columbia, have invented certain new and useful Improvements in Processes of Treating Fibrous Material, of which the following is a desori tion. V

y invention relates to the separation of fibers from the stalks of fiber bearing plants such as flax, ramie, jute, hemp, plta and other plants which contain fibers capable for use for the manufacture of textile fabrics, cordage or paper-and consists in the process hereinafter described and particularly pointed out in the claims.

The stalks of fiber bearing plants are composed in addition to the fibers, of woody material containing little or no fiber or at least none of commercial value but containing resinous or gummy substances and It is of course necessary to separate the fiber from this woody portion of the stalk in order to make use of the fiber and 'this separation of the fiber and woody material has been effected heretofore only with great difliculty and expense. For instance inorder to obtain from flax the fiber contained in it the only commercially practicable process has been that of slow rotting or retting of the Woody material under or in the presence of water. This process is expensive because of the length of time and the care and attention required and also because of the destruction by rotting of a considerable por tion. of the fiber. Because of the expense of separating the fiber the growing of flax for fiber has practically ceased for many years in the United States and while flax is extensively grown it is grown only for its seed and the straw is practically a waste produce. \Vhile attempts have heretofore been made to et rid of the woody material by chemical action the success of such attempts has not been such as to be commercially practical and the rettin process is still the only process ax fiber is obtained commercially.

By the process of the present invention it is now made ossible without in'ury to the fiber, to quickly and effectively issolve the resinous or gummy substances of the woody ortion of the stalk to such an extent that 1t is rendered friable and is detached from the fiber so that when the treated stalks or materially reduce the cost of treatment of a given quantity of flax but to also secure a much larger yield of fiber and to secure fiber of better quality than can be secured by the retting process.

In carrying out the process of the present invention the flax straw is taken as it comes from the field, either as dry straw or in a green state, and is placed, preferably in bundles or sheaves, in a tank and there boiled in an alkaline degumming solution for about an hour and a half, at the end of which time the degumming solution is drawn oil and clean Water introduced into the tank and agitated, preferably by introducing air under pressure at the bottom of the tank, so as to wash the treated straw to free it from the remains of the degumming solution. After thus washing the treated straw the Wash water is drawn off and an acid solution or sour bath solution is introduced into the tank and agitated so as to come in contact with all of the stalks or straws and neutralize any traces of alkali which might remain after the washing as wellas to aid in completing the dissolving of the resinous or gummy constituents of the woody portlon of the stalks or straws. After the sour bath solution has remained on the treated straw for about twenty minutes it is drawn off and the straw washed as before in clean water. The wash water having been drawn off a weak alkaline solution which may be termed a soap solution is introduced into the tank and allowed to remain for a short time only preferably not over 10 or 15 minutes, the soap solution bein preferably agitated while it remains on t e straw. The soap solution is then drawn off and the straw again washed. The chemical treatment of the straw is then complete and it only re-.

mains to separate the woody ortion or shive of the stalk from the her from which it has been loosened or detached by the action of the chemicals used. For this purpose the treated straw is dried by any convenient means and when dry the woody portion or shive is found to be so friable that it is easily separated from the fiber by the ordinar methods employed for freeing retted flax rom shives.

The fiber produced by the above described process is considerably greater in quantity than the amount produced by the retting rocess the chemicals used not attacking the fiber so that practically all of the fiber present in the stalk or straw is recovered as available for commercial use. The fiber produced by this process is much lighter in color than fiber produced by the rettlng process and is equally as strong if not stronger and is ready to be spun without bleaching though if deslred it may be bleached by any usual bleaching process.

It will be noted that in the process as above described no preliminary deshiving of the flax straw is contemplated or desired and that the whole straw is carried through the several steps of the process without any separation of the shives or Woody portion until the treatment is completed and the straw dried. By thus avoiding any mechanicaltreatment of the straw until it has been subjected to the complete chemical treatment any breaking of the fiber while 1t is still closely associated with the woody portion or shives is avoided.

The degumming solution is a solutlon 1n 20 gallons of water of five pounds caustic potash or caustic soda, 1 pound of borate of soda and 1 pounds of sal-soda. The proportion of water may be varied to make the solution stron er or weaker depending on the fibrous pl ant to be treated. The

most satisfactory results are obtained by adding to this solution kerosene oil and linseed oil in the proportions of J,- gallon of kerosene to 20 gallons of the solution and one quart of linseed oil. The kerosene appears to soften the resinous matters and to aid in dissolving them and the linseed Oll appears to soften the fiber and render it less likely to be injured in separating the shives from the dried straw.

The sour bath is a solution in 20 galions of water of 6 ounces of sulfuric acid, ounce of nitric acid and 4 ounces of acetic acid, though the proportion of Water may be varied somewhat to make the solution strlonger or weaker as may be found desirab e.

The soap solution is a solution of potash and sal-soda in proportion of one part each of the potash and the sal-soda to ninety-eight parts of water.

The process has been above particularly described as applied to flax, but it is found as to other fiber bearing plants the only scribed necessary in the treatment of fiber bearing plants other than flax being a varia tion in the strength of thedegummingsolution and the other solutions and a variation in the length of time required by the particular plant to be treated.

Having thus described the invention what I claim is:

1. The herein described process of degunnning fibrous plants which consists vin subjecting the stalks or straw to a boiling solution containing caustic potash, borate of soda and sal soda and also containing hydrocarbon oil and vegetable oil.

2. The herein described rocess of degumming fibrous plants which consists in subjecting the stalks or straw to a boiling solution containin' caustic potash, borate of soda and sal soda and'subsequently subjectingthe stalks or straw to an acid bath containing an organic acid.

3. The herein described process of degumming fibrous plants which consists in subjecting the stalks or straw to a boiling solution containing caustic potash, borate of soda and sal soda and subsequently subjecting the stalks or straw successively to an acid bath containing an organic acid and to an alkaline bath.

4. The herein described process of de gumming fibrous plants which consists in subjecting the stalks or straw to a boiling solution containing caustic potash, borate of soda and sal soda and also containing hydrocarbon oil and subsequently subjecting the stalks or straw to an acid solution containing an organic acid.

The herein described process of degunnning fibrous plants which consists in subjecting the stalks or straw to a boiling solution containing caustic potash, borate of sodaand sal soda and also containing hydrocarbon oil and subsequently subject ing the stalks or straw successively to an acid bath containing an organic acid and to an alkaline bath..

6. The herein described degumming solution containing caustic potash, borate of soda and s'al soda and also containing hydro- I carbon oil and a vegetable oil.

7. The herein described degumming solution containing caustic potash, borate of taining hydrocarbon oil and vegetable oil.

This specification signed and witnessed.

ROBERT R. ROBERTS.

In the presence of B. F. HAND,

. D. E. BEG-KWITH. 

